Enhancement of price trend trading strategies via image-induced importance weights
Enhancement of price trend trading strategies via image-induced importance weights
This paper introduces a novel method to enhance price trend trading strategies using image-induced importance (triple-I) weights derived from deep learning analysis of price chart images. The authors design a ResNet 'trader' that extracts general price patterns from historical price-volume images and generates localization maps via smooth Grad-CAM, which assign importance values to each spatial location for predicting upward or downward price movements. These importance weights are then used to compute a weighted moving average of existing trading signals (e.g., momentum, reversal, trend, and formulaic alphas), amplifying signals at more informative time points. Empirical analysis on the Chinese A-share market (2014-2023) shows that the TWMA method significantly improves portfolio performance: one-day Sharpe ratios increase by at least 219% for momentum and reversal strategies, and by 27-73% for trend and alpha strategies, while also reducing turnover. The method's robustness is confirmed across different network depths, image structures, and stock sizes. Furthermore, the triple-I weights enable effective transfer learning: time-scale transfer allows high-frequency models to enhance long-term (one-month) portfolios, and non-technical transfer improves news-based trading strategies by de-noising sentiment scores. Finally, the TWMA method is validated on 7,846 trading rules, consistently outperforming original and CNN-based signals. This work opens the 'black-box' of deep learning in technical analysis, providing a practical tool for traders to enhance their strategies using interpretable image-derived importance weights.
Highlights
- 1Proposes a ResNet 'trader' to extract general price patterns from price chart images, outperforming CNN-based approaches.
- 2Introduces image-induced importance (triple-I) weights derived from smooth Grad-CAM localization maps to enhance existing trading signals.
- 3Demonstrates significant improvement in Sharpe ratios (up to 219% higher) for momentum, reversal, and other trend strategies in Chinese stock market.
- 4Shows effectiveness of time-scale and non-technical transfer learning, enhancing long-term portfolios and news-based strategies.
- 5Validates the method across 7,846 trading rules, with TWMA-based signals significantly outperforming original and CNN-based counterparts.
Methods
- MResNet architecture (18, 34, 50 layers) for image classification of price chart images (5, 20, 60 days) to predict return direction.
- MSmooth Grad-CAM to generate upward and downward localization maps, computing triple-I weights as vertical averages of importance.
- MTriple-I weighted moving average (TWMA) to adjust trading signals (MOM, STR, WSTR, TREND, ALPHA) by amplifying important time points.
- MTransfer learning: time-scale (high-frequency to low-frequency) and non-technical (price charts to news sentiment) applications.
Results
- ROne-day TWMA-based portfolios achieve Sharpe ratios at least 219% higher than original signals for MOM, STR, WSTR; 27% for TREND; 73% for ALPHA.
- ROne-week TWMA-based portfolios show smaller turnover but no significant Sharpe improvement over original signals.
- RTime-scale transfer learning improves one-month portfolio Sharpe ratios from 0.16-0.98 to 0.21-1.05 across five signals.
- RNon-technical transfer learning enhances news-based strategies: Sharpe ratios increase from 1.72 to 2.04 (one-day) and 0.15 to 0.41 (one-week).
- RAcross 7,846 trading rules, TWMA-based signals (ResNet) yield mean Sharpe ratio of 0.25 vs. -0.10 (original) and -0.06 (CNN-based), with statistical significance.
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